Rhode Island - Fluvial Flood Depth 2 ft - Rhode Island Geographic Information System

The riverine flood hazard assessment is based on guidance issued in Executive Order 13690 – the Federal Flood Risk Management Standard – which provides recommendations for establishing flood elevation and hazard areas that account for uncertainties associated with future climate change. The new standard amends the definition of floodplain to include the following approaches to establish the vertical elevation and corresponding horizontal extent of flooding for federally funded projects:

Use data and methods informed by best-available, actionable climate science;

Build two feet above the 100-year (1%-annual-chance) flood elevation for standard projects, and three feet above for critical buildings like hospitals and evacuation centers; or

Build to the 500-year (0.2%-annual-chance) flood elevation.

The analysis described here corresponds with option 2, and was intended to complement recent hydrologic modelling conducted for the Rhode Island Department of Health SafeWater RI study (RIDOH, 2012). SafeWater RI developed estimates of future floodplains in the Pawtuxet River Basin using downscaled climate models; the results were then extrapolated to other watersheds in the state (option 1). By contrast, this approach used a consistent, map-based calculation, to delineate floodplains based on FEMA’s Base Flood Elevation (BFE) and the underlying topography. The mapping also extended to Special Flood Hazard Areas designated by FEMA as Zone A – areas subject to inundation by the 1-percent-annual-chance flood event that are determined using approximate methodologies and do not have assigned Base Flood Elevations.

The maps maybe inaccurate or contain errors or omissions. The user assumes full responsibility for the risks and damages that might result from using these maps or the underlying data. These maps are not flood insurance rate maps and should not be used in place of them. Official FEMA Flood Insurance Rate Maps for RI are provided at . RIGIS Use Constraints: This dataset is provided 'as is.’ The producer(s) of this dataset, contributors to this dataset, the Rhode Island Geographic Information System (RIGIS) consortium, the State of Rhode Island, and the University of Rhode Island do not make any warranties of any kind for this dataset, and are not liable for any loss or damage however and whenever caused by any use of this dataset. Please acknowledge both RIGIS and the primary producer(s) of this dataset in any derived products.